Hammer mill



1943. c, H. G AMBLE ET AL v I 2,307,400

HAMMER MILL Filed Feb. 14, 1940 FIG. I 56 36 zlyso I l/u Fla. 2

IN VENTOR: CARL H. GAMBLE ATTOIRNEYS.

Patented Jan. 5, 1943 HAMMER MILL Carl H. Gamble and Henry E..Korum, Moline; 111., assignors to Deere & Company, Moline, IlL, a corporation of Illinois Application February 14, 1940, Serial No. 318,876 7 Claims. (c1. 83-11) The present invention relates generally to feed grinding machines such as hammer mills and the like, and has for its principal object the provision of a hammer mill embodying certain new and useful improvements which materially increase its capacity for grinding certain fibrous materials such as hay, alfalfa, and the like.

Heretofore, in mills of this type, the feed chute has been composed of a tapered feed table mounted on the outside of the housing, and a restricted straight throat portion disposed within the housing and terminating at a point substantially directly above the rotor. We have found that the capacity of the mill for grinding fibrous material is greatly increased by tapering the feed chute at a more or less uniform rate from the outer portion of the feed table to the extreme inner end of the throat, thereby eliminating the restricted straight portion which has a choking effect tending to retard the fiow of material. One of the features of our invention, therefore, consists in providing a wide, outwardly flared feed throat in the rotor housing which lines up with the taper of the feed table.

Another object of the present invention is to provide an improved rotor housing construction in which the side walls are formed of heavy gauge sheet metal reenforced by a rigid strengthening member which serves also as a rotor shaft bearing support.

These and other objects and advantages of the present invention will become apparent after a consideration of the following detailed description of a preferred embodiment, reference being had to the accompanying drawing, in which Figure l is a side elevation of a hammer mill embodying the principles of our invention; and

Figure 2 is a plan view of the hammer mill with a portion of the housing broken away to show a section taken along the line 2-2 of Figure 1.

Referring now to the drawing, the reference numeral i3 indicates the rotor housing of the mill, the housing comprising a lower main casing H and an upper hood portion l2 hinged thereto for vertical swinging to allow the housing to be opened for inspection or adjustment. The main casing ii includes vertical side and end walls 13, ll, respectively, which may be formed of either sheet metal or boiler plate and may be fabricated from a single sheet of metal bent to the desired shape, or by welding or bolting severarplates together. The bottom edges of the side and end plates I3, l4, respectively, are flanged as at 9, providing a base for the mill. Preferably, the body or casing I I is bolted to wood skids 8 to provide ample support for the mill and facilitate its movement from one location to another. Fixed to the upper edge of each of the side walls I3 is a rigid strengthening or bracing member I5 which extends from one end.of the side wall to the other and is preferably in the form of a casting having an angle section. Each of the bracing members i5 has its midpoint bent to form a U-shaped bearing support portion ii having recessed shoulders I! which are adapted to carry the axially aligned rotor shaft bearings 20. The rotor bearings are each provided with a pair of mounting lugs 2| which rest on the shoulders I1 and are secured thereto by bolts 22. Preferably, the mounting lugs 2| engage the shoulders ll in a. plane through the axis of the rotor shaft, as shown in Figure 1.

The rotor shaft 23 is journaled in the bearings 20 and carries the rotor which is indicated in its entirety by the reference numeral 24, and is shown and described in detail in the co-pending application of Korum, Serial No. 165,857, filed September 2'7, 1937 and issued August 4, 1942 as Patent No.- 2,291,815. Reference may be had to the aforesaid application if desired, but inasmuch as the construction of the rotor has nothing to do with the present invention, it is deemed sufficient to state that the rotor consists of a plurality of triangular plates 25 spaced axially on the shaft 23 by circular spacers 26. Three banks of stepped hammers are carried by the rotor and rotate therewith to grind the material in a manner well known in the art. A generally semi-circular screen 3| is mounted in the lower casing H just below the rotor 24 for the purpose of determining the fineness of the material being ground.

The hood i2, like the lower housing II, is formed of sheet metal or boiler plate and has an open side or end 32 which is .pivotally connected by pivot bolts 33 with upwardly extending lugs 34 formed integrally with the bracing members H5 at one end of the housing. The upper side of the hood l2 slopes downwardly from its open end 32 toward the opposite side thereof, the top of the hood being indicated at 35. The end of the hood opposite the pivot 33 is firmly clamped to the casing by means of a hood lock 36 comprising a bolt lll pivoted at ll on a bracket 42 mounted on the end wall ll of the casing. A knob 43 isthreaded on the outer end of the bolt and has shoulders that engage a bracket 44 fixed to the hood top 35.

Material is fed to the rotor by means of a feed chute, indicated generally by the reference numeral 45, which is carried on the pivoted hood l2 and consists of an outwardly flared feed throat 46 and a tapered feed table 41. Fixed to the opposite side walls of the hood [2 adjacent the open end thereof is a circular baflle plate 50 which is substantially concentric with the rotor 24 and serves to provide a confined chamber within which the rotor turns. An upwardly inclined and outwardly diverging floor pan 6! is joined with the top of the baffle plate 50 and extends laterally therefrom toward the open end 32 of the hood, the sides of the pan 6| being suitably fixed to the sides of the hood. The inner end 52 of the floor pan is disposed substantially directly above the rotor shaft 23 and constitutes a discharge lip over which the material falls by gravity to meet the rotor. The sides of the hood I! between the floor pan and the hood top 35, are flared outwardly at 53 to form the sides of the throat 46.

The feed table 41 extends into the feed throat opening for a short distance and is secured to the hood by bolts 54. The sides 65 of the table are flared outwardly at substantially the same angle as the sides 53 of the feed throat, and are disposed to lie in juxtaposition therewith so as to provide a continuous, uninterrupted taper from the outer end of the feed table to the discharge lip 52. A shield 56 is fixed'to the upper edge of the feed table 41 adjacent the feed throat, and serves to deflect bulky material down into the feed throat. A baflle 60 is fixed by bolts 6| at its upper edge to the top wall 35 of the rotor hood l2 and curves downwardly toward the circular screen 3| with which it is Joined in any suitable manner.

The material that is fed into the mill and reduced by the hammers,'is drawn through the screen 3| and out of the mill casing by an exhaust fan unit indicated in its entirety by the reference numeral 62. The exhaust fan unit 62 includes a fan casing 63 which is mounted on the rotor housing wall I3 near the lower edge thereof and "communicates with the interior of .the housing through a suitable intake conduit (not shown). The blower fan is carried on a shaft 64 journaled in the fan casing 63 and is driven from the rotor shaft 23 through V-belts (not shown), trained over pulleys 65 mounted on the fan shaft 64 and companion pulleys (not shown) fixed to the rotor shaft 23. The fan casing 63 has an upwardly extending exhaust conduit 66 which conveys the groundmaterial away from the mill housing to the usual sacking or loading spouts.

It is believed that the advantages of the present invention will be apparent from the forego-' ing description. The gradual, easy taper of the feed chute 45 causes the hay or alfalfa to be bunched together with a minimum of frictional resistance, and the material is pulled through the most restricted portion of the feed throat, which is the portion of the throat at the discharge lip 52, by the flailing action of the rotor 24 as it turns in a counterclockwise direction.

What we claim as our invention and desire to secure by Letters Patent is:

said side walls, a curved screen extending around the lower half of the periphery of said rotor. a baflle extending from one end of said screen to the top of the housing substantially directly above the axis of the rotor, a second bailie extending from the other end of said screen to a point substantially directly above the axis of the rotor and closely adjacent the periphery thereof, a bottom pan disposed within said housing with one end closely adjacent the upper end of said second baiile and the other end flush with the end of the housin the side walls of said housing between said bottom pan and the top of the housing being flared outwardly from said one end of the bottom pan to the other end thereof.

3. In a feed mill having a housing including a pair of side walls and a rotor disposed between said side walls, a feed chute throat comprising a .bottom pan disposed within said housing and fixed to the side walls thereof, one edge of said bottom pan being positioned substantially directly above the axis of the rotor and the sides of said bottom pan diverging outwardly from said one edge, the side walls of the housing above said bottom pan being flared outwardly to register with the sides of the bottom pan.

4. In a feed mill having a housing including a pair of side walls and a rotor disposed between said side walls, a feed throat including a bottom pan disposed within said housing with one end substantially directly above the axis of the rotor and the other end flush with one end of the housing, the side walls of said housing above said bottom pan being flared outwardly from said one end of the bottom pan to the other end thereof, and a feed table mounted on said one end of the housing, said feed table having a bottom substantially forming a continuation of said bottom pan and outwardly diverging sides that line up with said flared portions of the side walls to form a continuation thereof.

5. In a feed mill having a housing including a pair of side walls and a rotor disposed between said side walls, a curved screen extending around the lower half of the periphery of said rotor, a battle extending from one end of said screen to a point above said rotor spaced radially from the periphery thereof, a second baiiie extending from the other end of said screen to a point above the rotor closely adjacent the periphery thereof, each of said housing side walls having a portion thereof bent outwardly along a line substantially connecting the upper ends of the baflles to form outwardly flared sides of a feed chute, and a bottom pan extending outwardly from the upper end of said second baffle, said bottom pan having edges diverging outwardly from the extreme inner end thereof and fixed to the lower edges of said outwardly flared portions of the side walls.

6. A hammer mill comprising a housing having substantially vertical side walls, a rotor disposed '7. In a feed mill having a housing including a pair of side walls and a rotor disposed between said side walls, a curved screen extending around the lower half of the periphery of said rotor, at bailie extending from one end of said screen to a point above said rot-or spaced radially from the periphery thereof, a second baifie extending from the other end of said screen to a point above the rotor closely adjacent the periphery thereof, and a feed chute for said feed mill comprising a bottom pan extending outwardly from the upper end of said second bafile, the'edges of said pan diverging outwardly from the extreme inner end thereof and disposed substantially entirely outside of the planes of said side walls, and feed chute side walls extending upwardly from the edges of said pan and diverging outwardly from said housing side walls, intersecting the latter along lines substantially connecting the upper ends of said baifles.

CARL H. GAMBLE. HENRY E. KORUM. 

